The present invention involves sump discharging methods and apparatus, especially for use in a marine vessel.
Marine vessels typically employ sump systems for discharging waste water (i.e., so-called "gray water") from sinks, showers, and the like. A sump system commonly employs a tank having an ingress for water to be discharged, and an egress in communication with a water discharge pump. The pump is energized in response to the sensing of an accumulation of water in the tank by means of a switch.
One type of switch which is currently utilized is a float switch wherein a float is mounted on the end of a lever. As the water rises, the float ascends to rotate the lever (e.g., see U.S. Pat. Nos. 3,941,073 and 4,275,995). When the lever has rotated a predetermined distance, electrical contacts are closed to energize the pump. Problems associated with such a switch involve a tendency for the switch to become fouled by substances in the water, whereupon the switch may tend to stick. Also, the switch is sensitive to momentary increases in water level occurring at the float in response to the motion of the vessel. Consequently, the switch may cycle on and off repeatedly and wear out relatively soon.
A known type of pump control mechanism utilizes a diaphragm which is acted upon and displaced by a water pressure head in the sump tank (e.g., see U.S. Pat. Nos. 2,687,693; 3,070,021; 3,104,614; 3,162,737; and 3,285,181). The diaphragm is associated with the switch so as to actuate the switch and energize the pump in response to a predetermined displacement of the diaphragm. Although such a mechanism may reduce the problems of switch fouling, there remains the problem of the switch being worn out by frequent actuation in response to momentary water level increases due to the motion of the vessel.
Therefore, it would be desirable to provide a sump pump actuating mechanism, especially for use in a marine vessel, which is relatively insensitive to momentary increases in water level. If the degree of such insensitivity could be varied, then the mechanism could be adapted to different types of vessels and different operating conditions. It would also be advantageous if such a mechanism were capable of being oriented in any direction in/on the sump tank, i.e., vertically or horizontally, as desired.
Another problem encountered in connection with the disposal of liquid from marine vessels relates to the fact that many vessels suffer from a lack of available vertical or horizontal space for accommodating a conventional sump system. That is, there may be available only a few inches of height in a bilge area, which height is too short to accommodate a standard height sump tank. It would be desirable to provide a sump system which can be accommodated in such a low space. Also, it would be desirable to provide a sump system in which it is unnecessary to gain access to the side of the tank for maintenance of the pump-energizing switch, whereby the tank can be employed in areas having little available horizontal space.
A further problem encountered in connection with conventional sump systems is the expulsion of undesirable odors from the sump tank into the surrounding atmosphere when the tank is being filled. Conventional sump tanks are open to the surrounding atmosphere either through a fully open or loosely closed tank top, whereby odors may be expelled from the tank into those areas. It would, therefore, be desirable to provide a sump system which avoids the emission of odors into the adjacent atmosphere.
Sump tanks usually require frequent cleaning to remove films, scum, soap residue, dirt particles, hair particles, food particles, etc., which may accumulate therein and which can eventually interfere with proper sump operation as well as produce noxious odors. It is both time-consuming and unpleasant to clean the tank interior, so it would be desirable to provide a self-cleaning sump apparatus.
Yet another problem associated with sump systems on marine vessels occurs when the sump tank is located in a volatile environment, such as a fuel storage area. In such an environment, the variety of pump-energizing mechanisms which can be used is limited, because it would not be permissible to utilize a mechanism of a type which generates electrical sparks that could produce an explosion. It would be desirable, therefore to be able to utilize a pump-energizing mechanism of the spark-generating type while eliminating the risk of explosions.